1. Field of the Invention
The present invention generally relates to systems and methods for determining information for defects on wafers.
2. Description of the Related Art
The following description and examples are not admitted to be prior art by virtue of their inclusion in this section.
Inspection processes are used at various steps during a semiconductor manufacturing process to detect defects on wafers to promote higher yield in the manufacturing process and thus higher profits. Inspection has always been an important part of fabricating semiconductor devices such as ICs. However, as the dimensions of semiconductor devices decrease, inspection becomes even more important to the successful manufacture of acceptable semiconductor devices because smaller defects can cause the devices to fail.
Some currently used inspection systems are configured to detect or suppress fluorescence signals from defects or wafer background. However, such tools generally do not have much flexibility in the wavelengths of light used for excitation and the wavelengths of emission that are detected by the tools. For example, some such tools are configured to illuminate a wafer with a single wavelength and include a limited number of spectral filters in the optical collection path. In addition, many such tools are not configured for inspection of patterned wafers containing rectilinear or other patterns that scatter light strongly or can otherwise cause noise in the output of the tools that increases the difficulty of detecting defects on the wafers.
Accordingly, it would be advantageous to develop methods and systems for determining information for defects on wafers that do not have one or more disadvantages described above.